Camshaft adjusting devices are generally known in which, using an actuating drive, the actual setting of a camshaft with respect to the rotation of the crankshaft is followed corresponding to a setpoint setting ascertained in a control unit.
In this context, in principle, two types of camshaft adjusting devices are known. In one type, the generating of camshaft adjustment takes place independently of other assemblies. For this, for example, electrical camshaft actuators may be used. The other type of camshaft adjusting devices are those in which the energy required for generating the camshaft adjustment is fed directly by an ancillary component of the internal combustion engine, such as, for instance, the oil-pressure pump of the engine oil circulation.
Independent of whether a camshaft adjusting device has its own drive or one that is coupled to other devices, the problem arises that, when inaccurate regulation occurs, first, the exhaust emission behavior of the vehicle changes, and, secondly, also the vehicle behavior with respect to engine power and the response behavior change. In this context, it is known that, when too great an impairment of the exhaust emission behavior of the internal combustion engine occurs, a fault indication detectable by the driver is generated that prompts him immediately to look for a repair shop to eliminate the problem.